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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Macromolecules 21 (1988), S. 392-397 
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Sedimentology 39 (1992), S. 0 
    ISSN: 1365-3091
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences
    Notes: Glacial gravels of Late Devensian Dimlington Stadial age (26 000–13 000 years BP) at West Tanfield, North Yorkshire, England, have been cemented by carbonate-rich solutions to produce a strongly indurated calcrete horizon. The low-Mg cements occur as drusy spar, needle fibres, alveolar septal structures, micrite and micropinnacles, indicative of vadose-zone cementation. Some complex pore partition structures attributed to precipitation along meniscus films also occur. These partitions separate air-dominated and water-dominated microenvironments of the vadose zone. The abundance of vadose fabrics shows that the accumulation is not a groundwater calcrete. In addition, much of the carbonate appears to have been precipitated by biological mediation.Carbon and oxygen isotopic data suggest that the carbonate did not form as a result of freezing, as has been suggested for some ‘arctic’soil carbonates. The pollen history of the area since the Devensian suggests that this calcrete precipitated at low temperatures; this contrasts with widely reported occurrences of calcrete in soils of hot arid or semi-arid regions, and suggests that palaeo-calcretes should not be used as absolute palaeoclimatic indicators.The unusual occurrence, albeit localized, of a thick calcrete under a cool and wet climate probably reflects the well-drained nature of the gravels, the abundance of CaCO3 as limestone clasts in the gravel and a high degree of biological activity beneath a forest cover, which created a local environment favouring carbonate precipitation.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Set-valued analysis 4 (1996), S. 25-39 
    ISSN: 1572-932X
    Keywords: Primary: 54C60, 54C65 ; secondary: 90D05 ; set-valued mapping ; selection theorem ; Banach spaces ; weak upper semi-continuity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract Set-valued mappings from a topological space into subsets of a Banach space which satisfy a restricted form of weak upper semi-continuity, have particularly noteworthy properties. We establish a ‘selection theorem’ for certain set-valued mappings from a (σ-β) unfavourable topological space into subsets of a Banach space and as a consequence derive the property that restricted weak upper semi-continuous set-valued mappings which satisfy a minimality condition, from a (σ-β) unfavourable topological space into subsets of a Banach space are single-valued and norm upper semi-continuous at the points of a residual subset of their domain.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Set-valued analysis 1 (1993), S. 365-378 
    ISSN: 1572-932X
    Keywords: 54C10 ; 54C65 ; Upper and lower semi-continuity ; minimal set-valved mappings ; selection theorems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract We modify the definitions of continuity and lower semicontinuity for single-valued mappings and upper and lower semicontinuity for set-valued mappings. For single-valued mappings we have a generalisation of Osgood's theorem and for set-valued mappings we have an extension of Fort's theorem and a generalisation of Michael's selection theorem producing a densely defined selection with a natural continuity property relative to the domain.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Mathematische Annalen 291 (1991), S. 463-473 
    ISSN: 1432-1807
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of radioanalytical and nuclear chemistry 233 (1998), S. 125b 
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A Gamma Spectroscopy Logging System (GSLS) has been developed to study sub-surface radionuclide contamination. The absolute counting efficiencies of the GSLS detectors were determined using cylindrical reference sources. More complex borehole geometries were modeled using commercially available shielding software and correction factors were developed based on relative gamma-ray fluence rates. Examination of varying porosity and moisture content showed that as porisity increases, and as the formation saturation ratio decreases, relative gamma-ray fluence rates increase linearly for all energies. Correction factors for iron and water cylindrical shields were found to agree well with correction factors determined during previous studies allowing for the development of correction factors for type-304 stainless steel and low-carbon steel casings. Regression analyses of correction factor data produced equations for determining correction factors applicable to spectral gamma-ray well logs acquired under non-standard borehole conditions.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 36 (1993), S. 130-138 
    ISSN: 1040-452X
    Keywords: Chimera ; Micromanipulation ; Pluripotency ; ICM ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Pluripotency of isolated rabbit inner cell masses (ICMs) and cultured (3 days) inner cell mass (ICM) cells was tested by injecting these donor cells into day 3.5 blastocysts (experiment 1) or day 3 morulae (experiment 2) to produce chimeric embryos. Injected (n = 107) and noninjected (n = 103) embryos were transferred to the opposite uterine horns of the same recipient females. Chimerism was determined by adenosine deaminase (ADA) isozyme analysis on fetal tissue and by eye pigmentation at midgestation. In experiment 1, 53% and 64%, respectively, of blastocysts injected with ICMs or cultured ICM cells developed to midgestation, compared with 52% and 48% for controls. Of these fetuses, four (31%) and one (6%), respectively, had ADA chimerism. In experiment 2,38% and 62%, respectively, of the morulae injected with ICMs or cultured ICM cells developed to midgestation, compared with 46% and 56% for control morulae. Six (43%) chimeric fetuses from morulae injected with ICMs were detected by ADA analysis, but 12 (86%) chimeric fetuses were detected by eye pigmentation, indicating that eye pigmentation was a more sensitive marker for chimerism than our ADA assay. None of the 14 fetuses recovered after injecting morulae with cultured ICM cells were chimeric with either marker. No chimeras developed from control embryos. These studies demonstrate (1) that pregnancy rates are not compromised by injection of blastocysts or morulae with ICMs or cultured ICM cells, (2) that chimeric rabbit fetuses can be produced by injecting ICMs into either blastocysts or morulae, and (3) that cultured ICM cells can contribute to embryonic development when injected into blastocysts. © 1993 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 41 (1995), S. 204-211 
    ISSN: 1040-452X
    Keywords: Rabbit embryos ; Blastocyst ; Inner cell mass cells ; Trophectoderm ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The proportion of total cells in the blastocyst allocated to the inner cell mass (ICM) and trophectoderm (TE) is important for future development and may be a sensitive indicator to evaluate culture conditions. The number of cells and their distribution within the two primary cell lineages were determined for the rabbit embryo developing in vivo after superovulation or nonsuperovulation or embryo transfer and compared with embryos developing in vitro. Comparisons were made with cultured embryos or embryos grown in vivo until 3.5, 4.0, and 4.5 days of age. Embryos from superovulated rabbits developed in vivo for 3.5, 4.0, and 4.5 days, respectively, had 361, 758, and 902 total cells (P〈0.05), and in nonsuperovulated rabbits 130, 414, and 905 total cells (P〈0.05), with increasing proportions of ICM cells over time (P〈0.05). One-cell embryos recovered from superovulated females and transferred to nonsuperovulated recipients developed more slowly with 70, 299, and 550 total cells after 3.5, 4.0, and 4.5 days of culture (P〈0.05), respectively. The proportion of ICM cells increased with age of the embryo. Corresponding values for one-cell embryos cultured in vitro resulted in 70, 299, and 550 total cells (P〈0.05). However, in vitro culture of morula-stage embryos in the presence of fetal bovine serum for 24 hr did not delay growth. In addition, the proportions of ICM/total cells were 0.17, 0.25, and 0.29 for embryos developing in vitro at 3.5, 4.0, and 4.5 days, respectively, similar to those for embryos developing in vivo at each of the three recovery times. These data establish for the first time the number and proportion of cells allocated to the ICM of the rabbit embryo developing in vivo or under defined conditions in vitro. © 1995 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 22 (1989), S. 51-57 
    ISSN: 0148-7280
    Keywords: sperm viability ; stain ; acrosome morphology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A simple dual stain procedure (DS) for simultaneously determining sperm viability and acrosomal status is described. The DS includes the use of the vital stain trypan blue to detect live and dead spermatozoa and Giemsa to detect the presence or absence of an acrosome. For staining, spermatozoa are washed, incubated with trypan blue, washed, dried onto slides, and subjected to Giemsa. Dead spermatozoa stain blue in the postacrosomal region while live spermatozoa remain unstained. The acrosome stains light purple-dark pink while acrosome-free sperm remain unstained. This staining pattern enables differentiation of spermatozoa which have undergone a true acrosome reaction (TAR) from those which have undergone a false acrosome reaction (FAR). Incubation of bull, boar, ram, and stallion spermatozoa for 60 minutes at 37°C in the presence of calcium ionophore A23187 increased the proportion of spermatozoa undergoing a TAR in all species except the stallion. Incubation of bull spermatozoa for up to 24 hours at 37°C resulted in a decrease over time in the percentage of live acrosome-intact spermatozoa and a simultaneous increase in the percentage of spermatozoa categorized as having undergone a TAR and FAR. The DS could be a useful technique in evaluating sperm viability and acrosomal status in fertilization and clinical studies.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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